Aquaculture Engineering

ODD-IVAR LEKANG, Associate Professor of Aquaculture Engineering, Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Norway.

• Preface xvii1 Introduction 11.1 Aquaculture engineering 11.2 Classification of aquaculture 11.3 The farm: technical components in a system 21.3.1 Land‐based hatchery and juvenile production farm 21.3.2 On‐growing sea cage farm 41.4 Future trends: increased importance of aquaculture engineering 61.5 This textbook 6References 72 Water Transport 92.1 Introduction 92.2 Pipe and pipe parts 92.2.1 Pipes 92.2.2 Valves 122.2.3 Pipe parts: fittings 142.2.4 Pipe connections: jointing 152.2.5 Mooring of pipes 152.2.6 Ditches for pipes 162.3 Some basic hydrodynamics 172.3.1 Boundary layer theory 172.3.2 Bernoulli’s equation 182.4 Water flow and head loss in channels and pipe systems 192.4.1 Water flow 192.4.2 Head loss in pipelines 202.4.3 Head loss in single parts (fittings) 232.4.4 Gravity feed pipes 232.5 Pumps 262.5.1 Types of pump 262.5.2 Some definitions 262.5.3 Pumping of water requires energy 292.5.4 Centrifugal and propeller pumps 302.5.5 Pump performance curves and working point for centrifugal pumps 322.5.6 Change of water flow or pressure 352.5.7 Regulation of flow from selected pumps 37References 393 Water Quality and Water Treatment: An Introduction 413.1 Increased focus on water quality 413.2 Inlet water 413.3 Outlet water 433.4 Water treatment 44References 464 Fish Metabolism, Water Quality and Separation Technology 474.1 Introduction 474.2 Fish metabolism 474.2.1 Overview of fish metabolism 474.2.2 The energy budget 494.3 Separation technology 494.3.1 What are the impurities in water? 504.3.2 Phosphorus removal: an example 51References 535 Controlling pH, Alkalinity and Hardness 555.1 Introduction 555.2 pH 555.2.1 Water dissolves in water 555.2.2 What is pH 565.2.3 The carbonate system 575.2.4 Total carbonate carbon 605.2.5 Open or closed system 605.2.6 A mathematical approach 635.2.7 pH of different water sources 645.2.8 Recommended pH for aquaculture 645.3 Alkalinity 655.3.1 How to avoid pH fluctuations 655.3.2 Titration is necessary 655.3.3 A buffer 665.3.4 The term equivalent weight 685.3.5 Alkalinity given as mg/L CaCO3 685.3.6 Alkalinity of different water sources 695.3.7 Recommended alkalinity for aquaculture 695.4 Hardness 695.4.1 The concentration of bivalent cations 695.4.2 Hardness may lead to precipitation 705.4.3 Hardness of different water sources 715.4.4 Recommended hardness 715.5 Chemical agents to use for regulation of pH, alkalinity and hardness 725.6 Examples of methods for pH adjustment 735.6.1 Lime 735.6.2 Sea water 755.6.3 Lye or hydroxides 765.6.4 pH regulation in RAS 76References 776 Removal of Particles: Traditional Methods 796.1 Introduction 796.2 Characterization of the water 806.3 Methods for particle removal in fish farming 806.3.1 Mechanical filters and microscreens 816.3.2 Depth filtration: granular medium filters 846.3.3 Settling or gravity filters 876.3.4 Integrated treatment systems 906.4 Hydraulic loads on filter units 916.5 Purification efficiency 926.6 Dual drain tank 926.7 Local ecological solutions 94References 947 Protein Skimming, Flotation, Coagulation and Flocculation 977.1 Introduction 977.1.1 Surface tension, cohesion and adhesion 997.1.2 Surfactants 1027.2 Mechanisms for attachment and removal 1027.2.1 Attachment of particles to rising bubbles by collision, typically in flotation 1037.2.2 Improving colloid and particle removal rates: pretreatment 1057.2.3 Attachment of surface‐active substances, typically in protein skimmers 1117.2.4 Particle attachment by nucleation 1127.3 Bubbles 1137.3.1 What is a gas bubble? 1137.3.2 Methods for bubble generation 1137.3.3 Bubble size 1157.3.4 Bubble coalescence 1157.4 Foam 1167.4.1 What is foam? 1167.4.2 Foam stability 1177.4.3 Foam breakers 1187.5 Introduction of bubbles affects the gas concentration in the water 1187.6 Use of bubble columns in aquaculture 1187.7 Performance of protein skimmers and flotation plants in aquaculture 1197.7.1 What is removed in inlet or effluent aquaculture water with the use of protein skimmers? 1197.7.2 Factors affecting the efficiency of protein skimming in aquaculture 1217.7.3 Use of ozone 1227.7.4 Bubble fractionation 1237.8 Design and dimensioning of protein skimmers and flotation plants 1237.8.1 Protein skimmers: principles and design 1237.8.2 Protein skimmers: dimensioning 1257.8.3 Flotation plant 1267.8.4 Important factors affecting design of a DAF plant 127References 1298 Membrane Filtration 1358.1 History and use 1358.2 What is membrane filtration? 1368.3 Classification of membrane filters 1378.4 Flow pattern 1398.5 Membrane shape/geometry 1408.6 Membrane construction/morphology 1428.7 Flow across membranes 1438.8 Membrane materials 1438.9 Fouling 1448.10 Automation 1468.11 Design and dimensioning of membrane filtration plants 1468.12 Some examples of results with membranes used in aquaculture 149References 1509 Sludge 1539.1 What is sludge 1539.2 Utilization of the sludge 1549.3 Dewatering of sludge 1559.4 Stabilization of sludge 1569.5 Composting of the sludge: aerobic decomposition 1569.6 Fermentation and biogas production: anaerobic decomposition 1589.7 Addition of lime 1599.8 Drying of sludge 1599.9 Combustion of sludge 1609.10 Other possibilities for treatment and utilization of the sludge 161References 16110 Disinfection 16310.1 Introduction 16310.2 Basis of disinfection 16410.2.1 Degree of removal 16410.2.2 Chick’s law 16410.2.3 Watson’s law 16510.2.4 Dose–response curve 16510.3 Ultraviolet light 16510.3.1 Function 16510.3.2 Mode of action 16510.3.3 Design 16610.3.4 Design specification 16610.3.5 Dose 16810.3.6 Special problems 16810.4 Ozone 16810.4.1 Function 16810.4.2 Mode of action 16910.4.3 Design specification 16910.4.4 Ozone dose 17010.4.5 Special problems 17010.4.6 Measuring ozone content 17210.5 Advanced oxidation technology 17210.5.1 Redox potential 17210.5.2 Methods utilizing AOT 17310.6 Other disinfection methods 17510.6.1 Photozone 17510.6.2 Heat treatment 17510.6.3 Chlorine 17510.6.4 Changing the pH 17610.6.5 Natural methods: ground filtration or constructed wetland 17610.6.6 Membrane filtration 176References 17611 Heating and Cooling 17911.1 Introduction 17911.2 Heating requires energy 17911.3 Methods for heating water 18011.4 Heaters 18111.4.1 Immersion heaters 18111.4.2 Oil and gas burners 18311.5 Heat exchangers 18311.5.1 Why use heat exchangers? 18311.5.2 How is the heat transferred? 18411.5.3 Factors affecting heat transfer 18411.5.4 Important parameters when calculating the size of heat exchangers 18511.5.5 Types of heat exchanger 18711.5.6 Flow pattern in heat exchangers 18911.5.7 Materials in heat exchangers 19011.5.8 Fouling 19111.6 Heat pumps 19211.6.1 Why use heat pumps? 19211.6.2 Construction and function of a heat pump 19211.6.3 Log pressure–enthalpy (p–H) 19311.6.4 Coefficient of performance 19411.6.5 Installations of heat pumps 19411.6.6 Management and maintenance of heat pumps 19611.7 Composite heating systems 19611.8 Chilling of water 199References 20112 Gas Exchange, Aeration, Oxygenation and CO2 Removal 20312.1 Introduction 20312.2 Gas exchange in fish 20312.3 Gases in water 20412.4 Gas solubility in water 20612.5 Gas transfer theory: aeration 21012.5.1 Equilibrium 21012.5.2 Gas transfer 21212.6 Design and construction of aerators 21312.6.1 Basic principles 21312.6.2 Change of gas composition in the water for testing purposes 21412.6.3 Evaluation criteria 21512.6.4 Example of designs for different types of aerator 21712.7 Oxygenation of water 22312.8 Theory of oxygenation 22412.8.1 Increasing the equilibrium concentration 22412.8.2 Gas transfer velocity 22412.8.3 Addition under pressure 22412.9 Design and construction of oxygen injection systems 22512.9.1 Basic principles 22512.9.2 Where to install the injection system 22512.9.3 Evaluation of methods for injecting oxygen gas 22712.9.4 Examples of oxygen injection system designs 22712.10 Oxygen gas characteristics 23112.11 Sources of oxygen 23112.11.1 Oxygen gas 23112.11.2 Liquid oxygen 23212.11.3 On‐site oxygen production 23412.11.4 Selection of source 235References 23613 Removal of Ammonia and Other Nitrogen Connections from Water 23913.1 Introduction 23913.1.1 Nitrogen connections 23913.1.2 Total nitrogen: Kjeldahl nitrogen 23913.1.3 Amount of NH3 in the water is pH dependent 23913.1.4 NH4+‐N 24013.1.5 Nitrogen, a part of a cycle 24113.1.6 Measurement of nitrogen compounds 24113.1.7 Reference values for aquaculture 24113.2 Biological removal of ammonium ion 24213.3 Nitrification 24213.4 Construction of nitrification filters 24413.4.1 Flow‐through system 24413.4.2 The filter medium in the biofilter 24513.4.3 Rotating biofilter (biodrum) 24613.4.4 Moving bed bioreactor (MBBR) 24613.4.5 Granular filters/bead filters 24813.5 Management of biological filters 24813.6 Example of biofilter design 24813.7 Denitrification 24913.8 Other bacteria cultures 25013.9 Inoculation and boosting of biological filters 25113.10 Chemical removal of ammonia 25113.10.1 Principle 25113.10.2 Construction 25113.11 Other methods 253References 25314 Recycling Aquaculture Systems: Traditional Recirculating Water Systems 25714.1 Introduction 25714.2 Advantages and disadvantages of re‐use systems 25714.2.1 Advantages of re‐use systems 25714.2.2 Disadvantages of re‐use systems 25814.3 Definitions 25914.3.1 Degree of re‐use 25914.3.2 Water exchange in relation to amount of fish or to supplied amount of feed 26014.3.3 Degree of purification 26014.3.4 Intensity of the RAS 26114.4 Theoretical models for construction of re‐use systems 26114.4.1 Mass flow in the system 26114.4.2 Water requirements of the system 26114.4.3 Connection between outlet concentration, degree of re‐use and effectiveness of the water treatment system 26214.5 Components in a re‐use system 26414.5.1 Freshwater, brackish water and seawater RAS 26714.6 Accumulation of substances, hydrogen sulphide problem and earthy taste removal 26714.6.1 Accumulation of substances 26714.6.2 Earthy taste removal 26714.6.3 The hydrogen sulphide problem 26814.7 Water maturation, disinfection and use of probiotics 26914.8 Design of a re‐use system 27014.9 Evaluation of performance of a RAS 272References 27315 Natural Systems, Integrated Aquaculture, Aquaponics, Biofloc 27515.1 Characterization of production systems 27515.2 Closing the nutrient loop 27515.3 Re‐use of water: an interesting topic 27515.4 Natural systems, polyculture, integrated systems 27715.4.1 Integrated multitropic aquaculture 27715.4.2 Biological purification of water: some basics 27815.4.3 Examples of systems utilizing photoautotrophic organisms: aquaponics 27915.4.4 Examples of systems utilizing heterotrophic bacteria: active sludge and bioflocs 27915.4.5 The biofloc system 281References 28316 Production Units: A Classification 28516.1 Introduction 28516.2 Classification of production units 28516.2.1 Intensive/extensive 28816.2.2 Fully controlled/semi‐controlled 28816.2.3 Land based/tidal based/sea based 28816.2.4 Other 28916.3 Possibilities for controlling environmental impact 29017 Egg Storage and Hatching Equipment 29117.1 Introduction 29117.2 Systems where the eggs stay pelagic 29217.2.1 The incubator 29317.2.2 Water inlet and water flow 29317.2.3 Water outlet 29417.3 Systems where the eggs lie on the bottom 29417.3.1 Systems where the eggs lie in the same unit from spawning to fry ready for start feeding 29517.3.2 Systems where the eggs must be removed before hatching 29817.3.3 Systems where storing, hatching and first feeding are carried out in the same unit 298References 29918 Tanks, Basins and Other Closed Production Units 30118.1 Introduction 30118.2 Types of closed production unit 30118.3 How much water should be supplied? 30318.4 Water exchange rate 30418.5 Ideal or non‐ideal mixing and water exchange 30518.6 Tank design 30618.7 Flow pattern and self‐cleaning 30818.8 Water inlet design 31018.9 Water outlet or drain 31218.10 Dual drain 31418.11 Other installations 315References 31519 Ponds 31719.1 Introduction 31719.2 The ecosystem 31719.3 Different production ponds 31819.4 Pond types 32019.4.1 Construction principles 32019.4.2 Drainable or non‐drainable 32019.5 Size and construction 32119.6 Site selection 32219.7 Water supply 32219.8 The inlet 32219.9 The outlet: drainage 32319.10 Pond layout 324References 32520 Sea Cages 32720.1 Introduction 32720.2 Site selection 32820.3 Environmental factors affecting a floating construction 32920.3.1 Waves 32920.3.2 Wind 33620.3.3 Current 33620.3.4 Ice 33820.3.5 Site classification 33920.4 Construction of sea cages 33920.4.1 Cage collar or framework 34020.4.2 Weighting and stretching 34120.4.3 Net bags 34220.4.4 Breakwaters 34620.4.5 Examples of cage constructions 34720.5 Mooring systems 35120.5.1 Design of the mooring system 35220.5.2 Description of the single components in a pre‐stressed mooring system 35420.5.3 Examples of mooring systems in use 36020.6 Calculation of forces on a sea cage farm 36020.6.1 Types of force 36220.6.2 Calculation of current forces 36320.6.3 Calculation of wave forces 36720.6.4 Calculation of wind forces 36720.6.5 Calculation of weight on materials in water 36820.7 Calculation of the size of the mooring system 36820.7.1 Mooring analysis 36820.7.2 Calculation of sizes for mooring lines 36920.8 Control of mooring systems 371References 37121 Feeding Systems 37521.1 Introduction 37521.1.1 Why use automatic feeding systems? 37521.1.2 What can be automated? 37521.1.3 Selection of feeding system 37521.1.4 Feeding system requirements 37621.2 Types of feeding equipment 37621.2.1 Feed blowers 37621.2.2 Feed dispensers 37621.2.3 Demand feeders 37821.2.4 Automatic feeders 37821.2.5 Feeding systems 38321.3 Feed control 38521.4 Feed control systems 38521.5 Dynamic feeding systems 386References 38622 Internal Transport and Size Grading 38922.1 Introduction 38922.2 The importance of fish handling 39022.2.1 Why move the fish? 39022.2.2 Why size grade? 39122.3 Negative effects of handling the fish 39422.4 Methods and equipment for internal transport 39522.4.1 Moving fish with a supply of external energy 39522.4.2 Methods for moving fish without the need for external energy 40522.5 Methods and equipment for size grading of fish 40622.5.1 Equipment for grading that requires an energy supply 40622.5.2 Methods for voluntary grading (self‐grading) 416References 41623 Transport of Live Fish 41923.1 Introduction 41923.2 Preparation for transport 41923.3 Land transport 42023.3.1 Land vehicles 42023.3.2 The tank 42023.3.3 Supply of oxygen 42123.3.4 Changing the water 42223.3.5 Density 42223.3.6 Instrumentation and stopping procedures 42323.4 Sea transport 42323.4.1 Well boats 42323.4.2 The well 42423.4.3 Density 42523.4.4 Instrumentation 42523.4.5 Recent trends in well boat technology 42623.5 Air transport 42623.6 Other transport methods 42723.7 Cleaning and re‐use of water 42823.8 Use of additives 429References 42924 Instrumentation and Monitoring 43124.1 Introduction 43124.2 Construction of measuring instruments 43224.3 Instruments for measuring water quality 43224.3.1 Measuring temperature 43324.3.2 Measuring oxygen content of the water 43324.3.3 Measuring pH 43424.3.4 Measuring conductivity and salinity 43524.3.5 Measuring total gas pressure and nitrogen saturation 43524.3.6 Spectrophotometers for water analysis 43624.3.7 Other 43924.4 Instruments for measuring physical conditions 43924.4.1 Measuring the water flow 44024.4.2 Measuring water pressure 44224.4.3 Measuring water level 44324.5 Equipment for counting fish, measuring fish size and estimation of total biomass 44424.5.1 Counting fish 44424.5.2 Measuring fish size and total fish biomass 44524.6 Monitoring systems 44824.6.1 Sensors and measuring equipment 44924.6.2 Monitoring centre 44924.6.3 Warning equipment 45124.6.4 Regulation equipment 45124.6.5 Maintenance and control 45124.7 Remotely operated vehicle (ROV) technology 451References 45225 Buildings and Superstructures 45525.1 Why use buildings? 45525.2 Types, shape and roof design 45525.2.1 Types 45525.2.2 Shape 45625.2.3 Roof design 45725.3 Load‐carrying systems 45725.4 Materials 45825.5 Prefabricate or build on site? 46025.6 Insulated or not? 46025.7 Foundations and ground conditions 46125.8 Design of major parts 46125.8.1 Floors 46125.8.2 Walls 46225.9 Ventilation and climate control 463References 46526 Design and Construction of Aquaculture Facilities: Some Examples 46726.1 Introduction 46726.2 Land‐based hatchery, juvenile and on‐growing production plant utilizing flow‐through technology 46726.2.1 General 46726.2.2 Water intake and transfer 46826.2.3 Water treatment department 47726.2.4 Production rooms 47926.2.5 Feed storage 48326.2.6 Disinfection barrier 48426.2.7 Other rooms 48426.2.8 Outlet water treatment 48426.2.9 Important equipment 48426.3 Land‐based juvenile and on‐growing production plant utilizing RAS technology 48626.3.1 Introduction 48626.3.2 Fish tanks and production department 48826.3.3 Water treatment department 48926.3.4 Retention time and number of turnover per day 49226.3.5 Heating/chilling 49326.3.6 H2S problem 49326.3.7 Sludge treatment system 49326.3.8 Fish handling 49426.3.9 Others 49426.4 On‐growing production, sea cage farms 49426.4.1 General 49426.4.2 Site selection 49426.4.3 The cages and the fixed equipment 49526.4.4 The base station 49826.4.5 Net handling 49926.4.6 Boat 500References 50127 Planning Aquaculture Facilities 50327.1 Introduction 50327.2 The planning process 50427.3 Site selection 50427.4 Production plan 50527.5 Room programme 50527.6 Necessary analyses 50527.7 Drawing up alternative solutions 50827.8 Evaluation of and choosing between the alternative solutions 51127.9 Finishing plans, detailed planning 51127.10 Function test of the plant 51127.11 Project review 511References 511Index 513